It's a little different: from when the rPI first came out the price was a big driver of it's popularity. It started with the Model B at $35 (with the Model A at $25 "later this year") and this was so much cheaper than other options at the time. Look over threads from the time [1][2] and you'll see things like: "I teach middle school programming/computer classes. I cannot wait to get my hands on one of these. Right now it's cheap enough that I can tell the parents to buy one for their kids without a problem, and out of pocket it for those few of my students whose parents won't be able to afford it." and "The pricepoint is simply revoultionary. I intend to make a few amateur home automation gadgets with this."

[1] https://news.ycombinator.com/item?id=2974292

[2] https://news.ycombinator.com/item?id=3448677